(I'm testing with Protractor and Jasmine, and I've also included image-diff and node-canvas in my project.)
I need to compare two images and make sure they are the same. One is saved in my file structure and the other is created from canvas. I am able to convert the canvas to image and also load the image from the file. Here's what I have:
var imagediff = require('../node_modules/js-imagediff/js/imagediff.js');
var Canvas = require('canvas');
var fs = require('fs');
var path = require('path');
beforeEach(function () {
jasmine.addMatchers(imagediff.jasmine);
});
function loadImage (url, callback) {
var image;
fs.readFile(url, function (error, data) {
if (error) throw error;
image = new Canvas.Image();
image.onload = function () {
callback(image);
};
image.src = data;
});
return image;
}
it('should work', function () {
//executeScript is needed to get the canvas element and convert it
browser.driver.executeScript(function() {
var can = document.querySelector('#workspace-canvas');
var ctx = can.getContext("2d");
var data = can.toDataURL("image/png");
var img = new Image();
img.src = data;
//this code below shows that the image was converted properly
// var link = document.createElement('a');
// link.href = img.src;
// link.download = 'image1.png';
// link.click();
return data;
}).then(function(result) {
newData = result;
var imgPath = path.join(__dirname, './images/image1.png');
loadImage(imgPath, function(image) {
console.log('loadImage');
var canvas = new Canvas();
canvas.width = image.width;
canvas.height = image.height;
var ctx = canvas.getContext("2d");
ctx.drawImage(image, 0, 0);
var data = canvas.toDataURL("image/png");
oldData = data;
//TODO: do a comparison here!
done();
});
});
My question is how do I compare the two images and make sure they are the same? I thought comparing the data URI would work but it doesn't. I'd really like to use image-diff but I'm not sure how to do that. Please help me!
The API of imagediff, has the imagediff.equal(a,b) function, that gets 2 Image objects, which should help you in this case.
If this won't help you, you could always md5 hash both of them and make sure the checksums are equal, more info on this md5, checksum.
Here's how I ended up doing it. I used fs.writeFile to save the new image to my project and then load that image and compare both images with image-diff.
var imagediff = require('../node_modules/js-imagediff/js/imagediff.js');
var Canvas = require('canvas');
var fs = require('fs');
var path = require('path');
beforeEach(function () {
jasmine.addMatchers(imagediff.jasmine);
});
function loadImage (url, callback) {
var image;
fs.readFile(url, function (error, data) {
if (error) throw error;
image = new Canvas.Image();
image.onload = function () {
callback(image);
};
image.src = data;
});
return image;
}
function writeFile (buffer, fileName) {
fs.writeFile(fileName, buffer, function (err) {
if(err) { console.log('ERROR', err); }
});
}
function dataURItoBuffer (dataURI, fileName) {
var byteString = dataURI.split(',')[1];
var buffer = new Buffer(byteString, 'base64');
writeFile(buffer, fileName);
}
it('should work', function () {
//fileName is defined somewhere else
var filePath = './images' + fileName + '.png';
//executeScript is needed to get the canvas element and convert it
browser.driver.executeScript(function() {
var can = document.querySelector('#workspace-canvas');
var ctx = can.getContext("2d");
var data = can.toDataURL("image/png");
return data;
}).then(function(result) {
dataURItoBuffer(result, fileName);
var oldImagePath = path.join(__dirname, './images/' + fileName + '.png');
var newImagePath = path.join(__dirname, filePath);
loadImage(oldImagePath, function(image) {
image1 = image;
loadImage(newImagePath, function(image){
image2 = image;
expect(imagediff.equal(image1, image2, 50)).toBeTruthy(); // 50 pixel tolerance
done();
});
});
});
});
Related
I am building a plugin for FIGMA, where the user selects multiple images, which I then save in an array, that I send to be interpreted.
I have 2 issues with my code
img.src = bin; does not trigger img.onload, but if I set img.src = "literal string", the onload method workds.
the imageData array sent at the end is undefined, I assume because of my bad understanding of async functions.
I would appreciate your help figuring this out. Thank you
P.S. this is pure javascript, and you don't need to know FIGMA to follow the code.
<input type="file" id="images" accept="image/png" multiple />
<button id="button">Create image</button>
<script>
const button = document.getElementById('button');
button.onclick = () => {
const files = document.getElementById('images').files;
function readFile(index) {
console.log(1);
if (index >= files.length) {return};
console.log(2);
const file = files[index];
const imageCaption = file.name;
var reader = new FileReader();
reader.readAsArrayBuffer(file);
reader.onload = function (e) {
console.log(4);
// get file content
const bin = e.target.result;
const imageBytes = new Uint8Array(bin);
//Get Image width and height
var img = new Image();
img.src = bin;
img.onload = function () {
console.log(6);
const width = img.width;
const height = img.height;
console.log("imageCaption: " + imageCaption);
console.log("width: " + width);
console.log("height: " + height);
console.log("imageBytes: " + imageBytes);
var data = {imageBytes, imageCaption, width, height};
//Read Next File
nextData = readFile(index + 1);
if( nextData ) {
data.concat(nextData)
}
return data;
}
}
}
//Call function to Read and Send Images
const imageData = readFile(0);
//Send Data
parent.postMessage({
pluginMessage: {
type: 'send-image',
imageData,
}
}, '*');
A friend ended up helping me with it. Thank you Hiba!
const button = document.getElementById('button');
const input = document.getElementById('input');
button.addEventListener('click', async () => {
const files = input.files ? [...input.files] : [];
const data = await Promise.all(
files.map(async (file) => await getImageData(file))
);
console.log(data);
});
async function getImageData(file) {
// get binary data from file
const bin = await file.arrayBuffer();
// translate bin data into bytes
const imageBytes = new Uint8Array(bin)
// create data blob from bytes
const blob = new Blob([imageBytes], { type: "image/png" });
// create html image element and assign blob as src
const img = new Image();
img.src = URL.createObjectURL(blob);
// get width and height from rendered image
await img.decode();
const { width, height } = img;
const data = { image: blob, caption: file.name, width, height };
return data;
}
I am new to coding in javascript, I have been tasked as an excersise using some pre-existing functions to create an image item using a given url. I need to read the image, store it in local storage and then display it on the screen. The only functionI need to add too is process file. I am stuck and cannot get it to display the image. I get an error saying that the path does not exist. Below is my code, any guidance to what I am doing wrong? I feel like I am very close but doing something funamendatly wrong.
function addImageEntry(key, url) {
var imgElement = new Image();
imgElement.alt = "Photo entry";
imgElement.src = url;
addSection(key, imgElement);
}
function makeItem(type, data) {
var itemObject = { type: type, data: data };
return JSON.stringify(itemObject);
}
function processFile(event) {
function addImage(url) {
var key = "diary" + Date.now();
addImageEntry(key, url);
var imgElement = new Image();
imgElement.src = url;
var item = makeItem("image", imgElement.src);
localStorage.setItem(key, item);
}
var inputElement = event.target;
var fileObject = inputElement.files[0];
var reader = new FileReader();
reader.addEventListener("load",addImage);
url = reader.readAsDataURL(fileObject);
event.target.value = "";
}
The url = reader.readAsDataURL(fileObject) won't store the image data.
It stores in reader.result.
Use imgElement.src = reader.result.
document.querySelector('input[type="file"]').addEventListener('change', processFile)
function processFile(event) {
var fileObject = event.target.files[0]
var reader = new FileReader()
reader.addEventListener('load', addImage)
reader.readAsDataURL(fileObject)
function addImage() {
var imgElement = new Image()
imgElement.src = reader.result
document.body.append(imgElement)
}
}
Amend:
function addImage(event) {
// use reader.result is ok too
localStorage.setItem('myimage', event.target.result)
}
function addImageEntry() {
var imgElement = new Image()
imgElement.src = localStorage.getItem('myimage')
imgElement.style.display = 'block'
document.body.append(imgElement)
}
On the client side, how can I use the native browser filesystem API to embed base64 image data within an IMG element?
function createIMGFromFS () {
var img = document.createElement("img");
const openFile = async () => {
const [fh] = await window.showOpenFilePicker();
var file2 = await fh.getFile();
var name = file2.name;
var fr = new FileReader();
fr.readAsDataURL(file2);
fr.onloadend = function() {
img.src = fr.result;
}
}
const file = openFile();
return img;
}
I am having problem in sending my base64 image from phonegap (ios) to firebase storage. The main problem is firebase storage only accepted BLOB or File as attachment.
Heres my code for the camera function. Cordova-plugin-camera
function GetCamera(){
navigator.camera.getPicture( cameraSuccess, cameraError, {quality :50,
destinationType: Camera.DestinationType.DATA_URL,
encodingType: Camera.EncodingType.JPEG,
saveToPhotoAlbum: true});}
function to convert base 64 to blob
function b64toblob(b64_data, content_type) {
content_type = content_type || '';
var slice_size = 512;
var byte_characters = atob(b64_data);
var byte_arrays = [];
for(var offset = 0; offset < byte_characters.length; offset += slice_size) {
var slice = byte_characters.slice(offset, offset + slice_size);
var byte_numbers = new Array(slice.length);
for(var i = 0; i < slice.length; i++) {
byte_numbers[i] = slice.charCodeAt(i);
}
var byte_array = new Uint8Array(byte_numbers);
byte_arrays.push(byte_array);
}
var blob = new Blob(byte_arrays, {type: content_type});
return blob;};
Camera success function. take note that imageblob is a global variable
function cameraSuccess(imageData){
document.getElementById('Attachment1').innerHTML = "Attachment: True";
var image = imageData;
imageblob = b64toblob(image,"image/jpeg");}
putting the blob to firebase storage
try{
var storageRef = storage.ref().child('fire');
var uploadTask = storageRef.put(imageblob);
uploadTask.on('state_changed',null, null, function(){
var downloadURL = uploadTask.snapshot.downloadURL;
console.log("downloadURL :"+downloadURL);
});
i have tried every single thing, but its not working. Really need your guys help.. i am out of ideas
Cordova camera plugin doesn't return file object. That is problem with plugin.
But it returns all details about image. By using that you can create a blob or file object.
Reference for creating blob from file url.
var getFileBlob = function (url, cb) {
var xhr = new XMLHttpRequest();
xhr.open("GET", url);
xhr.responseType = "blob";
xhr.addEventListener('load', function() {
cb(xhr.response);
});
xhr.send();
};
var blobToFile = function (blob, name) {
blob.lastModifiedDate = new Date();
blob.name = name;
return blob;
};
var getFileObject = function(filePathOrUrl, cb) {
getFileBlob(filePathOrUrl, function (blob) {
cb(blobToFile(blob, 'test.jpg')); // Second argument is name of the image
});
};
Calling function for get file blob
getFileObject('img/test.jpg', function (fileObject) { // First argument is path of the file
console.log(fileObject);
});
In your camera success function try this.
function cameraSuccess(imageData){
document.getElementById('Attachment1').innerHTML = "Attachment: True";
getFileObject(imageData.nativeURL, function(fileObject) {
console.log(fileObject);
var imgName = fileObject.name;
var metadata = { contentType: fileObject.type };
var uploadFile = storageRef.child("images/" + imgName).put(fileObject, metadata);
uploadFile.on(firebase.storage.TaskEvent.STATE_CHANGED, function(snapshot) {
var progress = (snapshot.bytesTransferred / snapshot.totalBytes) * 100;
console.log(progress);
}, function(error) {
console.log(error);
}, function() {
var imgFirebaseURL = uploadFile.snapshot.downloadURL;
console.log(imgFirebaseURL);
});
});
}
I have an file input that i used to get a file and turn it into a blob. Is there anyway I can get an external image url and turn that into a blob? Here is the code I am using to do it with just a file from a <input type="file" />:
//Process the file and resize it.
function processfile(file) {
if (!(/image/i).test(file.type)) {
alert("File " + file.name + " is not an image.");
return false;
}
// read the files
var reader = new FileReader();
reader.readAsArrayBuffer(file);
reader.onload = function (event) {
// blob stuff
var blob = new Blob([event.target.result]); // create blob...
window.URL = window.URL || window.webkitURL;
var blobURL = window.URL.createObjectURL(blob); // and get it's URL
// helper Image object
var image = new Image();
image.src = blobURL;
image.onload = function () {
for (var x = 0; x < self.ThumbSizes.length; x++) {
// have to wait till it's loaded
var resized = resizeMe(image, self.ThumbSizes[x]); // send it to canvas
var resized_blob = dataURItoBlob(resized);
uploadFile(resized_blob, self.ThumbSizes[x].Name);
}
}
};
Instead of passing a file through I wanted to be able to structure this code to pass a image url and convert it into a blob.
I hope it helps you. (I didn't run it.)
function processfile(imageURL) {
var image = new Image();
var onload = function () {
var canvas = document.createElement("canvas");
canvas.width =this.width;
canvas.height =this.height;
var ctx = canvas.getContext("2d");
ctx.drawImage(this, 0, 0);
canvas.toBlob(function(blob) {
// do stuff with blob
});
};
image.onload = onload;
image.src = imageURL;
}